Babies exposed to painkillers during the later stages of pregnancy appear to have an increased risk of developing schizophrenia in adulthood, according to the findings of a large Danish study published in the British Journal of Psychiatry.

To investigate the theory that prenatal exposure to analgesics might affect fetal neurodevelopment, leading to increased risk of schizophrenia in adulthood, the Copenhagen University team matched data from the Copenhagen Perinatal Cohort with information from the Danish Psychiatric Central Register.

Among a subset of 7999 individuals, 116 cases of schizophrenia were identified. Prenatal exposure to analgesics in the second trimester was associated with a nearly five-fold increased risk of schizophrenia.

The association remained statistically significant after factoring a parental history of schizophrenia and other risk factors.

Holger Sørensen and colleagues said that development of the cortical subplate reaches its peak in the second trimester, so the fetal brain might be particularly sensitive to a range of environmental influences in the womb at that time.

SOURCE: British Journal of Psychiatry, November 2004.